summaryrefslogtreecommitdiffstats
path: root/src/2geom/ellipse.cpp
diff options
context:
space:
mode:
Diffstat (limited to 'src/2geom/ellipse.cpp')
-rw-r--r--src/2geom/ellipse.cpp231
1 files changed, 112 insertions, 119 deletions
diff --git a/src/2geom/ellipse.cpp b/src/2geom/ellipse.cpp
index 2686844b2..4e26707ef 100644
--- a/src/2geom/ellipse.cpp
+++ b/src/2geom/ellipse.cpp
@@ -1,10 +1,11 @@
-/*
- * Ellipse Curve
- *
+/** @file
+ * @brief Ellipse shape
+ *//*
* Authors:
- * Marco Cecchetti <mrcekets at gmail.com>
+ * Marco Cecchetti <mrcekets at gmail.com>
+ * Krzysztof Kosiński <tweenk.pl@gmail.com>
*
- * Copyright 2008 authors
+ * Copyright 2008-2014 Authors
*
* This library is free software; you can redistribute it and/or
* modify it either under the terms of the GNU Lesser General Public
@@ -30,33 +31,28 @@
* the specific language governing rights and limitations.
*/
-
#include <2geom/ellipse.h>
#include <2geom/svg-elliptical-arc.h>
#include <2geom/numeric/fitting-tool.h>
#include <2geom/numeric/fitting-model.h>
-using std::swap;
+namespace Geom {
-namespace Geom
-{
-
-void Ellipse::set(double A, double B, double C, double D, double E, double F)
+void Ellipse::setCoefficients(double A, double B, double C, double D, double E, double F)
{
double den = 4*A*C - B*B;
- if ( den == 0 )
- {
- THROW_LOGICALERROR("den == 0, while computing ellipse centre");
+ if (den == 0) {
+ THROW_RANGEERROR("den == 0, while computing ellipse centre");
}
- m_centre[X] = (B*E - 2*C*D) / den;
- m_centre[Y] = (B*D - 2*A*E) / den;
+ _center[X] = (B*E - 2*C*D) / den;
+ _center[Y] = (B*D - 2*A*E) / den;
// evaluate the a coefficient of the ellipse equation in normal form
// E(x,y) = a*(x-cx)^2 + b*(x-cx)*(y-cy) + c*(y-cy)^2 = 1
// where b = a*B , c = a*C, (cx,cy) == centre
- double num = A * sqr(m_centre[X])
- + B * m_centre[X] * m_centre[Y]
- + C * sqr(m_centre[Y])
+ double num = A * sqr(_center[X])
+ + B * _center[X] * _center[Y]
+ + C * sqr(_center[Y])
- F;
@@ -64,73 +60,74 @@ void Ellipse::set(double A, double B, double C, double D, double E, double F)
double rot = std::atan2( -B, -(A - C) )/2;
// std::cerr << "rot = " << rot << std::endl;
bool swap_axes = false;
- if ( are_near(rot, 0) ) rot = 0;
- if ( are_near(rot, M_PI/2) || rot < 0 )
- {
+
+ if (rot >= M_PI/2 || rot < 0) {
swap_axes = true;
}
// evaluate the length of the ellipse rays
- double cosrot = std::cos(rot);
- double sinrot = std::sin(rot);
+ double sinrot, cosrot;
+ sincos(rot, sinrot, cosrot);
double cos2 = cosrot * cosrot;
double sin2 = sinrot * sinrot;
double cossin = cosrot * sinrot;
den = A * cos2 + B * cossin + C * sin2;
- if ( den == 0 )
- {
- THROW_LOGICALERROR("den == 0, while computing 'rx' coefficient");
+ if (den == 0) {
+ THROW_RANGEERROR("den == 0, while computing 'rx' coefficient");
}
- double rx2 = num/den;
- if ( rx2 < 0 )
- {
- THROW_LOGICALERROR("rx2 < 0, while computing 'rx' coefficient");
+ double rx2 = num / den;
+ if (rx2 < 0) {
+ THROW_RANGEERROR("rx2 < 0, while computing 'rx' coefficient");
}
double rx = std::sqrt(rx2);
den = C * cos2 - B * cossin + A * sin2;
- if ( den == 0 )
- {
- THROW_LOGICALERROR("den == 0, while computing 'ry' coefficient");
+ if (den == 0) {
+ THROW_RANGEERROR("den == 0, while computing 'ry' coefficient");
}
- double ry2 = num/den;
- if ( ry2 < 0 )
- {
- THROW_LOGICALERROR("ry2 < 0, while computing 'rx' coefficient");
+ double ry2 = num / den;
+ if (ry2 < 0) {
+ THROW_RANGEERROR("ry2 < 0, while computing 'rx' coefficient");
}
double ry = std::sqrt(ry2);
// the solution is not unique so we choose always the ellipse
// with a rotation angle between 0 and PI/2
- if ( swap_axes ) swap(rx, ry);
- if ( are_near(rot, M_PI/2)
- || are_near(rot, -M_PI/2)
- || are_near(rx, ry) )
- {
+ if (swap_axes) {
+ std::swap(rx, ry);
+ }
+
+ if (rx == ry) {
rot = 0;
}
- else if ( rot < 0 )
- {
+ if (rot < 0) {
rot += M_PI/2;
}
- m_ray[X] = rx;
- m_ray[Y] = ry;
- m_angle = rot;
+ _rays[X] = rx;
+ _rays[Y] = ry;
+ _angle = rot;
+}
+
+
+Affine Ellipse::unitCircleTransform() const
+{
+ Affine ret = Scale(ray(X), ray(Y)) * Rotate(_angle);
+ ret.setTranslation(center());
+ return ret;
}
-std::vector<double> Ellipse::implicit_form_coefficients() const
+std::vector<double> Ellipse::coefficients() const
{
- if (ray(X) == 0 || ray(Y) == 0)
- {
- THROW_LOGICALERROR("a degenerate ellipse doesn't own an implicit form");
+ if (ray(X) == 0 || ray(Y) == 0) {
+ THROW_RANGEERROR("a degenerate ellipse doesn't have an implicit form");
}
std::vector<double> coeff(6);
- double cosrot = std::cos(rot_angle());
- double sinrot = std::sin(rot_angle());
+ double cosrot, sinrot;
+ sincos(_angle, sinrot, cosrot);
double cos2 = cosrot * cosrot;
double sin2 = sinrot * sinrot;
double cossin = cosrot * sinrot;
@@ -150,18 +147,16 @@ std::vector<double> Ellipse::implicit_form_coefficients() const
}
-void Ellipse::set(std::vector<Point> const& points)
+void Ellipse::fit(std::vector<Point> const &points)
{
size_t sz = points.size();
- if (sz < 5)
- {
+ if (sz < 5) {
THROW_RANGEERROR("fitting error: too few points passed");
}
NL::LFMEllipse model;
NL::least_squeares_fitter<NL::LFMEllipse> fitter(model, sz);
- for (size_t i = 0; i < sz; ++i)
- {
+ for (size_t i = 0; i < sz; ++i) {
fitter.append(points[i]);
}
fitter.update();
@@ -172,12 +167,12 @@ void Ellipse::set(std::vector<Point> const& points)
EllipticalArc *
-Ellipse::arc(Point const& initial, Point const& inner, Point const& final,
+Ellipse::arc(Point const &ip, Point const &inner, Point const &fp,
bool _svg_compliant)
{
- Point sp_cp = initial - center();
- Point ep_cp = final - center();
- Point ip_cp = inner - center();
+ Point sp_cp = ip - center();
+ Point ep_cp = fp - center();
+ Point ip_cp = inner - center();
double angle1 = angle_between(sp_cp, ep_cp);
double angle2 = angle_between(sp_cp, ip_cp);
@@ -186,28 +181,19 @@ Ellipse::arc(Point const& initial, Point const& inner, Point const& final,
bool large_arc_flag = true;
bool sweep_flag = true;
- if ( angle1 > 0 )
- {
- if ( angle2 > 0 && angle3 > 0 )
- {
+ if (angle1 > 0) {
+ if (angle2 > 0 && angle3 > 0) {
large_arc_flag = false;
sweep_flag = true;
- }
- else
- {
+ } else {
large_arc_flag = true;
sweep_flag = false;
}
- }
- else
- {
- if ( angle2 < 0 && angle3 < 0 )
- {
+ } else {
+ if (angle2 < 0 && angle3 < 0) {
large_arc_flag = false;
sweep_flag = false;
- }
- else
- {
+ } else {
large_arc_flag = true;
sweep_flag = true;
}
@@ -215,66 +201,73 @@ Ellipse::arc(Point const& initial, Point const& inner, Point const& final,
EllipticalArc *ret_arc;
if (_svg_compliant) {
- ret_arc = new SVGEllipticalArc(initial, ray(X), ray(Y), rot_angle(),
- large_arc_flag, sweep_flag, final);
+ ret_arc = new SVGEllipticalArc(ip, ray(X), ray(Y), rotationAngle(),
+ large_arc_flag, sweep_flag, fp);
} else {
- ret_arc = new EllipticalArc(initial, ray(X), ray(Y), rot_angle(),
- large_arc_flag, sweep_flag, final);
+ ret_arc = new EllipticalArc(ip, ray(X), ray(Y), rotationAngle(),
+ large_arc_flag, sweep_flag, fp);
}
return ret_arc;
}
-Ellipse Ellipse::transformed(Affine const& m) const
+Ellipse &Ellipse::operator*=(Rotate const &r)
{
- double cosrot = std::cos(rot_angle());
- double sinrot = std::sin(rot_angle());
- Affine A( ray(X) * cosrot, ray(X) * sinrot,
- -ray(Y) * sinrot, ray(Y) * cosrot,
- 0, 0 );
- Point new_center = center() * m;
- Affine M = m.withoutTranslation();
- Affine AM = A * M;
- if ( are_near(std::sqrt(fabs(AM.det())), 0) )
- {
+ _angle += r.angle();
+ // keep the angle in the first quadrant
+ if (_angle < 0) {
+ _angle += M_PI;
+ }
+ if (_angle >= M_PI/2) {
+ std::swap(_rays[X], _rays[Y]);
+ _angle -= M_PI/2;
+ }
+ _center *= r;
+ return *this;
+}
+
+Ellipse &Ellipse::operator*=(Affine const& m)
+{
+ Rotate a(_angle);
+ Affine mwot = m.withoutTranslation();
+ Affine am = a * mwot;
+ if (are_near(am.descrim(), 0)) {
double angle;
- if (AM[0] != 0)
- {
- angle = std::atan2(AM[2], AM[0]);
- }
- else if (AM[1] != 0)
- {
- angle = std::atan2(AM[3], AM[1]);
- }
- else
- {
+ if (am[0] != 0) {
+ angle = std::atan2(am[2], am[0]);
+ } else if (am[1] != 0) {
+ angle = std::atan2(am[3], am[1]);
+ } else {
angle = M_PI/2;
}
- Point V(std::cos(angle), std::sin(angle));
- V *= AM;
- double rx = L2(V);
- angle = atan2(V);
- return Ellipse(new_center[X], new_center[Y], rx, 0, angle);
+ Point v;
+ sincos(angle, v[X], v[Y]);
+ v *= am;
+ _angle = atan2(v);
+ _center *= m;
+ _rays[X] = L2(v);
+ _rays[Y] = 0;
+ return *this;
}
- std::vector<double> coeff = implicit_form_coefficients();
- Affine Q( coeff[0], coeff[1]/2,
+ std::vector<double> coeff = coefficients();
+ Affine q( coeff[0], coeff[1]/2,
coeff[1]/2, coeff[2],
0, 0 );
- Affine invm = M.inverse();
- Q = invm * Q ;
- swap( invm[1], invm[2] );
- Q *= invm;
- Ellipse e(Q[0], 2*Q[1], Q[3], 0, 0, -1);
- e.m_centre = new_center;
+ Affine invm = mwot.inverse();
+ q = invm * q ;
+ std::swap(invm[1], invm[2]);
+ q *= invm;
+ setCoefficients(q[0], 2*q[1], q[3], 0, 0, -1);
+ _center *= m;
- return e;
+ return *this;
}
Ellipse::Ellipse(Geom::Circle const &c)
{
- m_centre = c.center();
- m_ray[X] = m_ray[Y] = c.ray();
+ _center = c.center();
+ _rays[X] = _rays[Y] = c.radius();
}
} // end namespace Geom
generated by cgit v1.2.3 (git 2.25.1) at 2026-05-19 01:33:17 +0000